JP7254518B2 - Additive manufacturing method for ceramics using microwaves - Google Patents

Description

The present specification relates to additive manufacturing methods, also known as 3D printing for ceramics.

Additive manufacturing (AM), also known as free-stereolithography or 3D printing, creates three-dimensional structures by continuously dispensing raw materials (e.g., powders, liquids, suspensions, molten solids) into two-dimensional layers. Refers to the manufacturing process by which an object is constructed. In contrast, conventional machining techniques involve subtractive processes in which objects are cut from a material (eg, blocks of ceramic, wood, plastic).

Various additive processes can be used in additive manufacturing. Also methods of melting or softening materials to produce layers, e.g. Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS), Selective Laser Sintering (SLS), Fused Deposition Modeling (FDM) There are also methods, if any, for curing liquid materials using different techniques, eg stereolithography (SLA). These processes may differ in the manner in which the layers are formed to produce the finished object and the materials that are compatible with use in the process.

Conventional systems use energy sources to sinter or melt powder materials. Once all selected locations on the first layer have been sintered or melted and then resolidified, a new layer of powder material is deposited over the completed layer. This process can then be repeated layer by layer until the desired object is produced.

SUMMARY In one aspect, an additive manufacturing apparatus for forming a ceramic part includes a platform that supports the ceramic part to be formed and a dispenser that dispenses a continuous layer of feed material onto the platform. The feedstock includes curable components. The apparatus further includes a radiation source that emits radiation directed toward the top surface of the platform and a microwave source that applies microwaves toward successive layers on the platform. The radiation is configured to cure the curable components of the feed material as or after each layer is delivered. The microwaves are configured to vaporize the curable components of the feed material and cause crystallization of the feed material to form the ceramic component.

In a further aspect, an additive manufacturing apparatus for forming a ceramic component includes an enclosure, an additive manufacturing module housed in the enclosure, a microwave module housed in the enclosure, and a controller. The additive manufacturing module is configured to dispense and cure successive layers of feedstock material on the platform. The microwave module is configured to radiate microwaves to cause crystallization of the feed material to form the ceramic component. The controller is configured to operate the additive manufacturing module to dispense and cure a layer of feed material to form a cured polymer. The controller is configured to operate the microwave module to vaporize the cured polymer and cause crystallization of the feed material after the layer of feed material has been delivered and cured to form the ceramic part.

In another aspect, an additive manufacturing method for forming a ceramic component includes the steps of delivering successive layers of feed material and, as or after each successive layer of the feed material is delivered, toward at least one layer of feed material. and applying microwaves directed at successive layers. The feedstock includes curable components. The radiation is configured to cure the curable component of the feed material. The microwaves are configured to vaporize the curable components of the feed material and cause crystallization of the feed material to form the ceramic component.

In yet another aspect, an additive manufacturing method includes providing a first layer of a first feedstock comprising a curable component and a ceramic component. The method further includes directing radiation toward the first layer of the first feed material to cure the curable components of the first feed material in the first layer. The method includes dispensing a second layer of a second feedstock over the first layer. A second feedstock includes a curable component and a ceramic component. The method further includes directing radiation toward the second layer of the second feed material to cure the curable components of the second feed material in the second layer. The method also includes delivering a third layer of the first feed material over the second layer of the second feed material and emitting radiation toward the third layer of the first feed material to produce a third layer of the first feed material. Curing the curable components of the first feed material in three layers. The method includes applying microwaves to a plurality of layers, including at least a first layer, a second layer, and a third layer, to crystallize and sinter a ceramic component of the feedstock of the plurality of layers. include.

Implementations of the apparatus and methods can include those described below and elsewhere herein. In some examples, the apparatus applies at least two layers of feed material to the dispenser between each application of microwaves such that the microwaves simultaneously vaporize curable components of at least two layers of feed material. A controller configured to cause dispensing can be included. The method may further include delivering at least two layers of feed material prior to applying microwaves. Applying microwaves can include applying microwaves to simultaneously vaporize the curable components of the at least two layers of the feed material. Alternatively or additionally, the apparatus is configured to cause the microwave source to apply microwaves to cause the dispenser to dispense all successive layers of feed material, followed by simultaneous vaporization of the curable components of successive layers of feed material. controller. Applying microwaves can include applying microwaves after all successive layers of feed material have been delivered to simultaneously vaporize the curable components of the layers of feed material.

In some examples, the additive manufacturing apparatus further comprises a controller configured to cause the microwave source to apply microwaves to cause growth of ceramic crystals transparent to microwaves to form the ceramic component. Application of microwaves can induce the growth of microwave-transparent ceramic crystals to form ceramic components. Radiation can be configured to cure the curable component to form a cured polymer. Exposing to radiation can include applying radiation to the feed material to cure a curable component of the feed material to form a cured polymer. The ceramic crystal can have a microwave transparency that is 400% to 2000% higher than the microwave transparency of the cured polymer.

In some examples, the microwave source can be configured to emit microwaves at multiple frequencies. The microwave source can be configured to sequentially emit microwaves at each of the frequencies. Applying microwaves can include radiating microwaves at a plurality of frequencies. Emitting microwaves at the frequencies can include sequentially emitting microwaves at each of the frequencies. The frequency is 5.8-6.8 Gigahertz. The microwave source can emit microwaves at each of the frequencies for approximately 25 microseconds. Emitting microwaves at the frequencies can include radiating microwaves at each of the frequencies for approximately 25 microseconds. Optionally, the microwave source can emit microwaves at each of the frequencies for 5 microseconds to 45 microseconds. Emitting microwaves at the frequencies can include radiating microwaves at each of the frequencies for 5 microseconds to 45 microseconds.

In some examples, the radiation source can be an ultraviolet (UV) light source, and the radiation is ultraviolet light. Emitting radiation can include emitting ultraviolet light toward at least one layer of the feed material upon or after delivering each layer of the successive layers. The curable component of the feedstock can include a UV light curable polymer.

In some examples, the feedstock can include ceramic components. A microwave source may be configured to radiate microwaves toward the platform to cause crystallization of the ceramic component. Crystallization of the ceramic component can be induced by applying microwaves. The ceramic component can include a liquid phase ceramic compound. The ceramic component of the feed material can include a first precursor material and a second precursor material. The microwave source can be configured to radiate microwaves toward the platform to cause the first precursor material and the second precursor material to form a ceramic compound. By applying microwaves, the first precursor material and the second precursor material can form a ceramic compound. The first precursor material can include carbon and the second precursor material can include silicon.

Additionally or alternatively, the feedstock can be a first feedstock and the dispenser can be configured to dispense the first feedstock and the second feedstock onto the top surface of the platform. Each of the first feedstock and the second feedstock can include a ceramic component and a curable component. The microwave source is configured to crystallize the ceramic component of the first feedstock to form first ceramic crystals and to crystallize the ceramic component of the second feedstock to form second ceramic crystals. can do. Application of microwaves causes the ceramic component of the first feedstock to crystallize to form first ceramic crystals and the ceramic component of the second feedstock to crystallize to form second ceramic crystals. can be formed. The first crystal can be larger than the second crystal. The first crystal can be 300% to 2000% larger than the second crystal. The ratio of ceramic component to curable component of the first feedstock can be greater than the ratio of ceramic component to curable component of the second feedstock. For example, the ratio of the first feedstock is 600% to 1000% greater than the ratio of the second feedstock.

In some cases where the first feedstock and the second feedstock are delivered, the apparatus can further include a controller. The controller causes the apparatus to dispense a first layer of the first feed material onto the top surface of the platform using the dispenser and cure the first layer of the first feed material using the radiation source. can be configured as The controller is configured to dispense a second layer of the second feed material onto the first layer using the dispenser and to cure the second layer of the second feed material using the radiation source. can do. The controller further uses the dispenser to dispense a third layer of the first feed material onto the second layer and uses the radiation source to cure the third layer of the first feed material. Can be configured. The controller can be further configured to sinter multiple layers, including at least the first layer, the second layer, and the third layer, using the microwave source.

In some cases where a first feedstock and a second feedstock are delivered, the method comprises delivering a first layer of the first feedstock, It can further include the step of emitting radiation towards it. The method can include delivering a second layer of a second feed material over the first layer and emitting radiation toward the second layer of the second feed material. The method can also include delivering a third layer of the first feedstock over the second layer and radiating the third layer of the first feedstock. The method can include sintering layers including at least a first layer, a second layer, and a third layer.

In some examples, the device can include an enclosure that is opaque to microwaves. An enclosure may support the platform and isolate microwaves emitted by the microwave source from the environment. Emitting microwaves can include radiating microwaves such that the microwaves are contained within an enclosure that isolates the microwaves from the environment of the enclosure.

In some examples, the device can include a window that is opaque to microwaves and transparent to at least infrared light. Emitting microwaves can include radiating microwaves such that the microwaves are contained within the enclosure and the windows of the enclosure. The window may be opaque to microwaves and transparent to at least infrared light. The apparatus may include an infrared thermal sensor that emits infrared radiation through the window toward the top surface of the platform. An infrared thermal sensor can be configured to detect the temperature of the feed material on the platform. The method may further include emitting infrared radiation through the window to detect the temperature of the feed material.

In some examples, the device can include a horn coupled to the microwave source. Emitting microwaves can include radiating microwaves through a horn. The horn can be shaped to direct microwaves emitted by the microwave source to a portion of the upper surface of the platform.
In some examples, the ceramic component is a silicon carbide monolith.
In some examples, the ceramic component is a tungsten carbide monolith.

Implementations described herein may optionally include (and are not limited to) the advantages described below. The additive manufacturing apparatus and method can reduce the material waste that typically occurs in subtractive processes for forming ceramic parts. For example, conventional machining methods may remove ceramic material from a ceramic workpiece to form a ceramic component, and the removed ceramic material may in some cases not be reusable. In contrast, the additive manufacturing apparatus and methods described herein do not remove the ceramic component in the feedstock delivered to form the continuous layer, but rather use it to form the ceramic part. be done.

The viscosity of the delivered feedstock can be adjusted by selecting the proportion of non-ceramic components in the feedstock. If the ceramic component is a liquid phase ceramic compound, the viscosity of the liquid phase ceramic compound alone can slow the dispensing rate and lead to clogging. In the additive manufacturing apparatus and method of the present invention, the feedstock is adjusted to a lower viscosity so that any equipment in the feedstock flow path is less likely to suffer from clogging that can occur at higher viscosities. can be made to have The lower viscosity of the feed material can further facilitate the throughput of forming ceramic parts by increasing the rate at which the feed material can be dispensed.

Microwaves can increase the rate of crystallization of ceramic components, especially compared to heat-based methods that do not use microwaves. When microwaves are applied at multiple frequencies, a more uniform energy and heat distribution across the layer of feed material can be achieved. Uniformity of energy and heat can increase uniformity of vaporization of the curable component and crystallization of the ceramic component. The more uniform the distribution of heat and energy to the ceramic component, the smoother the finish of the ceramic part can be. Without being limited by a particular theory, the increased uniformity may be due to microwaves causing multiple modes of reaction from the curable and ceramic components of the feedstock.

When multiple types of feedstock are delivered, the multiple types of feedstock can facilitate improved bonding between the delivered layers. In particular, the feedstocks have different compositions and ceramic component contents to form relatively small grains and relatively large grains. A crystalline structure formed from a combination of relatively small grains and relatively large grains is stronger than a crystalline structure with relatively large grain size homogeneity.

The details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other potential aspects, features, and advantages of the present subject matter will become apparent from the description, drawings, and claims.

It is a schematic side view of an additive manufacturing apparatus. 1 is a block diagram of a system of additive manufacturing equipment; FIG. 1 is a perspective view of a microwave horn for additive manufacturing equipment; FIG. 1 is a perspective view of a microwave horn for additive manufacturing equipment; FIG. 1 is a perspective view of a microwave horn for additive manufacturing equipment; FIG. 1 is a perspective view of a microwave horn for additive manufacturing equipment; FIG. 1 is a perspective view of a microwave horn for additive manufacturing equipment; FIG. 1 is a flow diagram of an example additive manufacturing process performed using additive manufacturing equipment; 4 is a graph representing the operation of an example additive manufacturing process performed using additive manufacturing equipment. 5B is a flow diagram of the additive manufacturing process represented in FIG. 5A;

Like reference numbers and designations in the various drawings indicate like elements.

Additive manufacturing (AM) equipment can be used to perform a manufacturing process that forms ceramic parts by dispensing and melting successive layers of feed material. The apparatus may use a first process to harden a portion of the feed material, thereby stabilizing the feed material after it has been dispensed. The apparatus can use a second process to cause crystallization of the stabilized feedstock and remove other materials from the feedstock that do not form ceramic parts.

Stabilization of the feedstock by curing and crystallization of the feedstock by exposure to microwaves can be processes that can affect different components of the feedstock in different ways. In some examples, the curing process can include emitting radiation that cures a curable component of the feed material, and the crystallization process includes emitting radiation that causes crystallization of a ceramic component of the feed material, for example. may include the step of

The curing radiation can comprise ultraviolet light and the feed material can comprise a photopolymer that cures in response to exposure to the curing radiation. The crystallization radiation can include microwaves, and the feedstock can include one or more ceramic components that crystallize to form a ceramic component in response to the microwaves. In some instances, ceramic crystals formed from microwaves can be transparent to microwaves, while cured polymers are opaque to microwaves. As a result, the microwaves can energize the cured polymer to vaporize it without burning the ceramic crystals. As a result, a significant portion of the non-ceramic components of the feedstock can be removed so that the ceramic crystals can form ceramic parts with ceramic material properties. For example, substantially only ceramic crystals can remain after a series of curing and crystallization processes.
Additive manufacturing equipment

FIG. 1 shows a schematic side view of an example additive manufacturing apparatus 100 capable of performing curing and crystallization processes to form ceramic parts. The additive manufacturing device 100 includes an additive manufacturing module 104 of the device 100 and an enclosure 102 that houses the microwave module 106 of the device 100 . The additive manufacturing module 104 dispenses a continuous layer 108 of feed material 110 onto a platform 112 for curing. By curing the continuous layer 108 of the feed material 110, the additive manufacturing module 104 forms a cured polymer. The cured polymer stabilizes layers 108 of feed material 110 as they are supported on platform 112 . The microwave module 106 emits microwaves toward the platform 112 to vaporize the cured polymer. The microwaves also cause crystallization of the ceramic component of the feedstock 110, inducing the formation of ceramic crystals that define the ceramic component. Referring to FIG. 2, which depicts control system 114, controller 116 of control system 114 can operate each of additive manufacturing module 104 and microwave module 106 to form a ceramic part. Control system 114 is described in greater detail herein.

Enclosure 102 supports platform 112 and is opaque to microwaves emitted by microwave module 106 . For example, enclosure 102 can be a metal mesh that acts as a Faraday cage. As a result, enclosure 102 serves to isolate microwaves from the environment outside the enclosure.

As shown in FIGS. 1 and 2, additive manufacturing module 104 includes dispenser 118 that dispenses layer 108 of feed material 110 onto platform 112 . Platform 112 and/or dispenser 118 are movable by a linear actuator or other drive mechanism capable of moving dispenser 118 horizontally over platform 112 . Optionally, the vertical position of platform 112 and/or dispenser 118 is adjustable. Accordingly, the vertical position of the dispenser 118 relative to the platform 112 allows the platform 112 to be lowered or the dispenser 118 to be raised so that the platform 112 is dispensed after each layer 108 of the feed material 110 is dispensed and cured. It is controllable to be ready to receive a new layer 108 of material 110 . This allows, for example, feed material 110 for each layer to be dispensed from the same height above platform 112 .

Dispenser 118 may include an opening through which feed material 110 is dispensed onto platform 112 by, for example, gravity. In some examples, dispenser 118 can be connected to a reservoir that stores supply material 110 . The release of feed material 110 can be controlled by a gate. Once the dispenser 118 has been translated to the position specified by the CAD compatible file, an electronic control signal can be sent to the gate to dispense the feed material 110 . In some examples, to control the release of feed material 110 from dispenser 118, the gate of dispenser 118 includes a piezoelectric printhead and/or a pneumatic valve, a microelectromechanical system (MEMS) valve, a solenoid valve, or a It can be provided by one or more of the solenoid valves. The opening of the dispenser 118 can be sized and dimensioned according to the viscosity of the feed material 110 .

In some implementations, the opening of the dispenser 118 extends across the width of the platform 112 or the usable build area of the platform 112 . Dispenser 118 , in this case, moves forward and backward to allow the opening of dispenser 118 to dispense feed material 110 along any portion of the usable build area of platform 112 . In some cases, the opening extends only partially across the width of platform 112 . As a result, dispenser 118 moves in a horizontal plane above platform 112, such as two vertical horizontal Move along an axis.

A dispenser 118 can dispense a feed material 110 that includes curable and ceramic components. Feedstock 110 may be a liquid, eg, completely liquid, or a suspension of particles in a liquid. In some examples, the curable component is a liquid photopolymer. The photosensitive polymer is sensitive to ultraviolet radiation such that radiation source 120 cures the photosensitive polymer when it emits ultraviolet light toward platform 112 . The photopolymer may be a UV photocurable polymer.

The additive manufacturing module 104 also includes a radiation source 120 that emits radiation toward the platform 112 to cure the feed material 110 . In some implementations, the radiation source 120 is an ultraviolet (UV) light source and the radiation is ultraviolet light. UV light can, for example, have a wavelength of 10 nm to 400 nm (eg, 10 to 320 nm, 320 to 400 nm, 320 nm to 360 nm, 340 nm to 380 nm, 380 nm to 400 nm, 350 nm to 370 nm, approximately 355 nm, approximately 365 nm). The wavelength of UV light selected can correspond to the type of photopolymer used as the UV photocurable polymer.

In some implementations, additive manufacturing module 104 and/or dispenser 118 dispenses a number of voxels of feed material 110 to form a layer of feed material 110 . When delivered onto platform 112, each voxel can have a width of, for example, 10 μm to 50 μm (eg, 10 μm to 30 μm, 20 μm to 40 μm, 30 μm to 50 μm, approximately 20 μm, approximately 30 μm, or approximately 50 μm). . Each layer can have a predetermined thickness. The thickness can be, for example, 10 μm to 125 μm (eg, 10 μm to 20 μm, 10 μm to 40 μm, 40 μm to 80 μm, 80 μm to 125 μm, approximately 15 μm, approximately 25 μm, approximately 60 μm, or approximately 100 μm).

Radiation source 120 can emit radiation to cure the curable components of feed material 110 as or after each layer 108 is dispensed by dispenser 118 . In some examples, radiation source 120 is a laser that cures the curable components as each layer is dispensed by dispenser 118 . Radiation source 120 is, for example, a UV light laser that emits a beam of UV light toward platform 112 . The beam of UV light covers an area of platform 112 that is smaller than the usable build area of platform 112 . When radiation source 120 is a UV light laser, radiation source 120 can emit multiple beams of UV light to cure a single layer of feed material 110 . When dispenser 118 dispenses multiple portions of feed material 110 to form layers of feed material 110 , radiation source 120 may, for example, emit a beam of UV light after dispenser 118 dispenses each portion of feed material 110 . radiate. This portion can be sized, for example, by a predetermined number of voxels so that the area covered by the beam of radiation from the radiation source 120 is larger than the area covered by the predetermined number of voxels. It can contain voxels.

In other embodiments, the radiation source 120, when activated, emits a light beam that covers an area whose width extends over the usable build area. In other embodiments, radiation source 120 emits a light beam that, when activated, covers the entire available build area. Radiation source 120 can thus cure the curable components after each layer is delivered. Radiation source 120 can be, for example, a UV light lamp that emits UV radiation. If the emitted radiation from the radiation source 120 covers the usable build area during activation of the radiation source 120, the radiation source 120 is activated after the dispenser 118 dispenses all of the layer supply material 110. be able to. If the radiation from radiation source 120 extends across the width of the build region, radiation source 120 can scan horizontally as layer 112 is delivered.

A ceramic component includes one or more materials that can form ceramic crystals that form a ceramic component. The ceramic component that forms the ceramic crystal may be a ceramic compound or one or more precursors for a ceramic compound. For example, the ceramic compound may be a liquid phase ceramic precursor, or the ceramic compound may be ceramic particles that dissolve during manufacture. The feedstock 110 optionally includes seed crystals that promote crystallization of the ceramic compound to form ceramic crystals.

In some embodiments, the ceramic component is formed from the ceramic material silicon carbide. Accordingly, dispenser 118 can dispense a feed material comprising one or more silicon carbide precursors and/or silicon carbide particles in these embodiments. The silicon carbide precursor can include a liquid phase silicon carbide precursor. When the ceramic component is formed from silicon carbide, the silicon carbide precursors include poly(silylacetylene)siloxane, polymethylsilane, [SiH1.26(CH3)0.6(CH2CH=CH2)0.14CH2]n, [ SiH1.26(CH3)0.6(CH2CH=CH2)0.14CH2]n, and one or more of polytitanium carbosilane (HPTiCS).

In some cases, the feedstock includes a carbon source and a silicon source that are precursors of silicon carbide. A carbon source and a silicon source under appropriate conditions can form silicon carbide crystals. A carbon source and a silicon source, for example, form silicon carbide in the presence of heat. Microwaves, such as microwaves from microwave module 106, can react the carbon source and the silicon source to form a silicon carbide compound or precursor. Microwaves can also induce crystal growth of the resulting silicon carbide compound or precursor.

In some embodiments, when the feedstock includes separate carbon and silicon sources, apparatus 100 optionally applies heat to feedstock 110 to form silicon and carbon sources to form silicon carbide. including a heat source that causes a reaction between A heat source can cause a reaction to form a silicon carbide compound, and then microwave module 106 can cause crystallization of the silicon carbide compound.

Ceramic components that continue to form ceramic crystals can be relatively transparent to radiation from radiation source 120 . In addition, the curable component contains a photoinitiator that is sensitive to radiation from the radiation source so that the curing radiation is curable without inducing chemical reactions in the ceramic component that crystallize the ceramic component. Components can be cured.

The curable component comprises about 1% to 30% by weight of the feed material 110 (e.g., 1% to 3%, 3% to 30%, 10% to 30%, 25% to 30%, by weight). %, etc.). The ceramic component comprises about 10% to 98% by weight of the feedstock 110 (e.g., 10% to 30%, 30% to 50%, 50% to 75%, 75% to 98% by weight). etc.).

Also shown in FIGS. 1 and 2, microwave module 106 includes microwave source 122 controllable by control system 114 that applies microwaves directed at platform 112 . The microwaves can vaporize the curable components of feed material 110 . Microwaves can also cause crystallization of the feed material 110 to form a ceramic component.

In some cases, the microwaves vaporize the photopolymer when it is in its cured state. The microwaves cause crystallization of the ceramic components in feed material 110 . Microwaves can cause nucleation of ceramic components. The microwave source 122 can also cause the growth of microwave transparent ceramic crystals by radiating microwaves toward the feed material 110 .

The curable component and the ceramic component can differ in their transparency to microwaves so that the microwaves can vaporize the curable component while inducing the formation of ceramic crystals. The ceramic crystals formed during crystallization can have a microwave transparency that is 400% to 2000% greater than the microwave transparency of the curable component after the curable component is cured. In other words, the ceramic crystal can have a microwave transparency that is 400% to 2000% higher than the microwave transparency of the cured polymer.

The microwaves emitted by the microwave source 122 can be frequency controlled such that the microwaves vary over a wide range of frequencies. For example, the microwave source 122 can be connected to a frequency controller 124 that modulates the frequency of the microwaves. In some examples, frequency controller 124 is part of controller 116 .

Microwave source 122 can be controlled by frequency controller 124 such that microwave source 122 sequentially emits microwaves at each of the selected frequencies within a predetermined frequency range. Microwaves can, for example, radiate at 100-5000 different frequencies within a given frequency range (e.g., 100-3000 different frequencies, 3000-5000 frequencies, 4000-4200 frequencies, approximately 4096 frequencies). can. The predetermined frequency range is 5.8-6.8 Gigahertz. In some examples, microwave source 122 emits microwaves at each frequency for approximately 25 microseconds. In some implementations, the microwave source 122 emits microwaves at each frequency for 5-45 microseconds (eg, 5-25 microseconds, 15-35 microseconds, or 25-45 microseconds). However, in some examples, microwaves can also be emitted at a fixed frequency, eg, 5.8-6.8 gigahertz.

In some examples, the microwaves emitted by microwave source 122 can cause multiple ceramic crystals to form within the layer of feed material 110 . The microwaves can add sufficient heat to the feed material 110 to vaporize the hardening polymer and sinter the plurality of ceramic crystals formed during the crystallization process. Thus, multiple ceramic crystals can be sintered together to form a solid mass of ceramic crystals.

In some cases, microwave source 122 applies microwaves to cover the entire available build area of platform 112 . In this case, after additive manufacturing module 104 has delivered and cured all of the layer or layers of feed material 110, microwave source 122 may be activated to apply microwaves. Optionally, after the additive manufacturing module 104 completes one or more layers of feed material 110 but before the additive manufacturing module begins dispensing and curing operations for another layer of feed material 110 , the micro A wave source 122 can be activated. In some embodiments, microwave source 122 emits microwaves that cause crystal growth and polymer vaporization through layers immediately below the top layer of feed material 110 . In such cases, microwave source 122 can be activated after multiple layers of feed material 110 have been dispensed and cured.

In some embodiments, both additive manufacturing module 104 and microwave module 106 are coupled to linear actuators that move modules 104 , 106 horizontally relative to platform 112 . Platform 112 can be held in a horizontal position within enclosure 102 as modules 104 , 106 are moved through enclosure 102 relative to platform 112 .

Microwave source 122 is moveable relative to platform 112 . In some examples, platform 112 is coupled to a linear actuator that can move platform 112 through enclosure 102 . After additive manufacturing module 104 dispenses and cures layer 108 , linear actuator moves platform 112 from under additive manufacturing module 104 to under microwave module 106 to receive microwaves from microwave module 106 . A layer 108 can be provided.

Microwave source 122 optionally emits microwaves through microwave horn 125 to direct the microwaves across the length and width of platform 112 . 3A-3E represent various examples of microwave horns 125a-125e that can be used with microwave source 122. FIG. Microwave horns 125 a - 125 e include flared metal waveguides shaped like horns to direct microwaves in beams toward platform 112 . Horns 125 a - 125 e may be shaped to direct microwaves emitted by microwave source 122 to portions of platform 112 . Apertures at the ends of the flared metal waveguides can determine the pattern of electric (E-field) and magnetic (H-field) fields at the mouths of horns 125a-125e. The microwave horns 125a-125 have different flare angles and different expansion curves (eg, elliptical, hyperbolic, and other expansion curves) in the E and H field directions to enable emission of a wide range of microwave beam profiles. can have

FIG. 3A depicts a pyramidal horn 125a having the shape of a square pyramid with a rectangular cross-section flared outward. Pyramidal horn 125a can be used with a rectangular waveguide to emit linearly polarized radio waves. FIG. 3B represents an E-plane horn 125b flared in the direction of the waveguide's electric or E-field. FIG. 3C represents H-plane horn 125c, which is a sector horn. A sector horn is a pyramidal horn with only one pair of sides flared and the other pair of sides parallel. The fan horn produces a fan beam that is narrow in the plane of the flared sides and wide in the plane of the narrow sides. H-plane horn 125c is a fan-shaped horn flared in the direction of the H-field in the waveguide. FIG. 3D represents a conical horn 125d whose conical shape has a circular cross-section. Conical horn 125d can be used with a cylindrical waveguide. FIG. 3E represents an exponential or scalar horn 125e with curved sides in which the side separation increases as an exponential function of length. Scara horn 125e can have a pyramidal or conical cross-section. The scalar horn 125e can have minimal internal reflection, nearly constant impedance, and other characteristics over a wide frequency range.

Optionally, apparatus 100 also includes sensing system 126 that detects properties of feed material 110 as feed material 110 undergoes various processes performed by additive manufacturing module 104 and microwave module 106 . Sensing system 126 may include optical sensor 128 . Sensor 128 is, for example, an infrared sensor 128 that detects infrared radiation emitted by feed material 110 on platform 112 . Sensor 128 , for example, determines the temperature of layer 108 of feed material 110 and allows control system 114 to monitor the operation of modules 104 , 106 . In some examples, sensor 128 is an infrared emitter and detector that can be used to determine the surface texture of feed material 110 on platform 112 .

In some embodiments, apparatus 100 includes windows 130 along enclosure 102 that allow optical monitoring of feed material 110 . Window 130 can be, for example, a quartz window with a conductive mesh that provides a Faraday cage. This allows window 130 to be opaque to the microwaves emitted by microwave module 106 . Quartz is transparent to microwaves, but the Faraday cage blocks microwaves from passing through window 130 . In this regard, window 130 allows optical monitoring without allowing microwaves to escape to the environment outside device 100 . In some examples, optical sensor 128 may be positioned outside enclosure 102 and emit an optical signal toward platform 112 through window 130 . Thus, window 130 may be transparent to optical signals emitted by optical sensor 128 but opaque to microwaves emitted by microwave module 106 . Window 130 is transparent, for example, to the infrared light emitted by the photosensor.

Controller 116 operates additive manufacturing module 104 to dispense and cure multiple layers 108 of feed material 110 , thereby forming an intermediate state of layers 108 of feed material 110 . In this intermediate state, layer 108 of feed material 110 comprises a cured polymer that stabilizes the structure and geometry of feed material 110 . The controller 116 operates the microwave module 106 to vaporize the cured polymer and cause the feed material 110 to crystallize after the multiple layers 108 have been delivered and cured. Ceramic crystals formed from the crystallization of the feed material 110 remain after the controller 116 operates the microwave module 106 because the cured polymer is vaporized. For a given layer, the remaining ceramic crystals form part of the ceramic component.

In some implementations, the control system 114 controls the additive manufacturing module 104 and/or the microwave module 106 using computer aided design (CAD) compatible files to form the ceramic part. For example, additive manufacturing module 104 can selectively dispense feedstock 110 to predetermined locations on platform 112 according to a printed pattern, which can be stored in a non-transitory computer-readable medium as a CAD compatible file. In some cases, the additive manufacturing module 104 can selectively cure the feedstock at predetermined locations on the platform 112 based on the print pattern determined in the CAD compatible file. Optionally, microwave module 106 also applies microwaves according to instructions from a CAD compatible file.
How to use additive manufacturing equipment

The additive manufacturing apparatus 100 and other apparatuses described herein can perform additive manufacturing processes to produce ceramic parts. Control system 114 controls the operation of additive manufacturing module 104 , microwave module 106 , and platform 112 , for example, to dispense, cure, and crystallize feed material 110 . In some examples, control system 114 may control the operation of dispenser 118 , radiation source 120 , and microwave source 122 . FIG. 4 is a flow diagram representing a process 400 of dispensing, curing, and crystallizing feedstock. Process 400 is performed, for example, by control system 114 that controls additive manufacturing apparatus 100 to dispense, cure, and crystallize feed material 110 .

Process 400 begins with a first layer of feedstock being dispensed (400A). For example, in operation 400A, control system 114 operates additive manufacturing module 104 to dispense a layer of feed material 110 (400A). Control system 114 may control dispenser 118 of additive manufacturing module 104 to dispense a layer of feed material 110 . A first layer of feed material 110 can be dispensed uniformly onto platform 112 (400A).

The first layer of feed material is then cured (400B) by application of ultraviolet light. Control system 114, for example, operates additive manufacturing module 104 to emit ultraviolet light toward platform 112 to cure the first layer of feed material 110 dispensed in operation 400A, thereby curing the feed material. 110 is stabilized. Control system 114 may operate radiation source 120 of additive manufacturing module 104 to emit radiation to cure the curable component of feed material 110 .

A second layer of feed material is then dispensed (400C). Control system 114 continues to control additive manufacturing module 104 to dispense a layer of feed material 110 by controlling dispenser 118 (400C). Prior to dispensing 400C the second layer, control system 114 may control actuators coupled to platform 112 and/or dispenser 118 to change the vertical position of dispenser 118 relative to platform 112 . In particular, the control system 114 controls the dispenser 118 and the platform 112 such that the dispenser 118 is positioned above the first layer that has been dispensed so that the second layer can be dispensed on top of the first layer. The actuator can be controlled to increase the distance between

In some examples, dispense operation 400A and apply operation 400B may be repeated several times before dispense operation 400C is performed. For example, if the radiation source 120 is a UV light laser, the control system 114 can sequentially perform the dispense and apply operations 400B to dispense and cure a portion of the first layer of the feed material 110 . By repeating these operations 400A, 400B, the control system 114 may operate the additive manufacturing module 104 to dispense and cure the entire first layer of feed material 110 . For example, the radiation source 120 can deliver a predetermined number of voxels of the feed material 110, and the predetermined number of voxels of the feed material 110 can form part of a layer of the feed material 110. . A portion of the layer of feed material 110 can have a sufficiently small area so that the light beam from radiation source 120 can cover the entire area. In some examples, radiation source 120 emits a light beam that covers the entire available build area. In such a case, control system 114 performs dispense operation 400A to dispense the entire first layer of feed material 110 and then performs application operation 400B to dispense the entire first layer of feed material 110 once. hardens to

After the second layer of feed material is delivered (400C), UV radiation is applied to the second layer of feed material (400D). Similar to application operation 400B, application operation 400D may include operation of additive manufacturing module 104 and/or radiation source 120 .

In some examples, the radiation emitted by the radiation source 120 can induce a curing process of the feed material 110 of the top layer as well as the layers below the top layer. As a result, instead of sequentially performing first dispensing operation 400A, first applying operation 400B, second dispensing operation 400C, and second applying operation 400D, control system 114 controls additive manufacturing module 104. , the first delivery operation 400A and the second delivery operation 400C are sequentially performed. The control system 114 then performs a single application operation 400B, 400D that cures both the first and second layers of feed material 110, eg, simultaneously.

After the first and second layers of feed material 110 are delivered (400A, 400C) and UV light is applied to cure the first and second layers (400B, 400D), microwaves are applied. 400E is applied to the first and second layers. Control system 114 , for example, operates microwave module 106 to radiate microwaves toward platform 112 . The microwaves cause the ceramic component of the feed material 110 to crystallize and the curable component of the feed material 110 to vaporize, as described above. Accordingly, control system 114 may cause dispenser 118 to dispense at least two layers of feed material 110 (400A, 400C) between each application of microwaves (400E). Thus, the microwaves can simultaneously vaporize the curable components of two or more layers of feed material 110 and crystallize the ceramic components of two or more layers of feed material 110 simultaneously. Crystallization of the ceramic component results in the formation of ceramic crystals that form the ceramic component.

In some examples, operations 400A-400D use additive manufacturing module 104 and operation 400E uses microwave module . Accordingly, in operations 400A-400D, control system 114 controls platform 112, additive manufacturing module 104, and microwave module 106 can be controlled. The additive manufacturing module 104 can dispense feedstock 110 and direct UV light to the platform 112 , while the microwave module 106 can direct microwaves to the platform 112 so that it cannot emit microwaves toward the platform 112 . can be placed against Control system 114 may control, for example, dispenser 118 and/or one or more linear actuators coupled to one or more of radiation source 120 , platform 112 , and microwave source 122 . In these cases, in preparation for operation 400 E, control system 114 may operate modules 104 , 106 and/or platform 112 such that microwave module 106 may radiate microwaves toward platform 112 . can. The additive manufacturing module 104 may also be positioned with respect to the platform 112 such that the additive manufacturing module 104 cannot dispense and cure the feed material 110 on the platform 112 .

In the process 400 depicted in FIG. 4, microwaves are applied (400E) after multiple layers have been delivered and cured. In some examples, microwaves are applied after each layer of feed material 110 is dispensed and cured.

In some examples, the ceramic component may be formed from two layers of feed material 110, so only operations 400A-400E may be required. Although only operations 400A-400E are shown, process 400 can be repeated multiple times such that more than two layers of feed material 110 are dispensed, cured, and crystallized. The actions of delivering (400A, 400C), applying UV light (400B, 400D), and applying microwaves (400E) can be repeated to produce a ceramic part formed from three or more layers of feed material 110. can.

In some examples where three or more layers of feed material 110 are dispensed and cured, control system 114 controls additive manufacturing module 104 to dispense and cure the curable components of each layer of feed material 110 . can be done. After dispensing and curing feed material 110 for all layers to be dispensed, control system 114 controls microwave module 106 to apply microwaves to simultaneously vaporize the curable components of all layers. be able to. Thus, in this case, microwaves can penetrate the top layer and at least two layers directly below the top layer.

In some implementations of additive manufacturing apparatus 100, additive manufacturing module 104 and dispenser 118 can dispense a single type of feed material 110 onto platform 112, as described herein. Optionally, additive manufacturing module 104 and dispenser 118 dispense additional types of feed materials. Dispenser 118 can dispense both the first feed material and the second feed material. A first feed material may be dispensed from a first opening of dispenser 118 and a second feed material may be dispensed from a second opening of dispenser 118 .

Each of the two feedstocks contains a curable component and a ceramic component. The first and second feedstocks differ in that the first feedstock can contain a density of ceramic components that is greater than the density of the ceramic components in the second feedstock. The ratio of ceramic component to curable component in the first feedstock is different than the ratio of ceramic component to curable component in the second feedstock. In some examples, the ratio of the first feedstock is 600% to 1000% greater than the ratio of the second feedstock.

In the first feedstock, the mass ratio of curable component to ceramic component may be between 1-10 and 1-3. In the second feedstock, the mass ratio of curable component to ceramic component may be between 1-3 and 1-1. The ratio of curable components to ceramic components in the first feedstock is 10% to 1000% (eg, 10% to 200%, 200% higher than the ratio of curable components to ceramic components in the second feedstock). ~600%, 600%-1000%) can be increased.

In some examples, the ceramic component of the first feedstock comprises polymethylsilane and the ceramic component of the second feedstock comprises [CH3(CH=CH)SiO]4. In some examples, the ceramic component of the first feedstock comprises [SiH1.26(CH3)0.6(CH2CH=CH2)0.14CH2]n and the ceramic component of the second feedstock comprises Cp2TiCl2 and/or vinylferrocene.

If only one feedstock is used, the feedstock can include a ceramic crystallite speed to increase crystallization rate and improve crystallization uniformity. If more than one feedstock is used, optionally one or both of the feedstocks contain ceramic crystal seeds. The two feedstocks can contain different densities of ceramic crystal seeds. The first feedstock delivered to the first and third layers can have a ceramic crystalline seed density that is greater than the ceramic crystalline seed density of the second feedstock delivered to the second layer. . In some embodiments, the first feedstock comprises ceramic crystal seeds and the second feedstock does not comprise ceramic crystal seeds.

The crystallization of the first feedstock is formed from the crystallization of the second feedstock because the first feedstock has a ceramic component proportion greater than the ceramic component proportion in the second feedstock. This can result in ceramic crystals that are larger than ceramic crystals. The additive manufacturing equipment 100 can take advantage of the difference in grain size between the ceramic crystallites of the first and second feedstocks to facilitate bonding and sintering between the layers of the feedstocks. Particle size heterogeneity between layers can improve the strength of the bond between the layers of the feedstock. Figures 5A and 5B show an example process 500 using two types of feedstock. In particular, FIG. 5A schematically represents a graph of delivery and application operations and relative durations for performing each of these operations. FIG. 5B shows a flow diagram of process 500 .

Process 500 begins with a first layer of feed material being dispensed (500A). A first layer is formed from a first feedstock. UV radiation is then applied to the first layer of the first feed material (500B). A second layer of feed material is then dispensed (500C). A second layer is formed from a second feedstock. UV radiation is then applied to the second layer of the second feed material (500D). Finally, a third layer of feedstock is delivered (500E), the third layer being formed from the first feedstock. UV radiation is then applied (500F) to the third layer of the third feed material. In operation 500G, microwaves are applied to cause crystallization of the ceramic components in the feedstock in each of the first, second and third layers. Dispensing operations 500A, 500C, 500E are similar to dispensing operations 400A, 400C described herein, except that the feed material dispensed in dispensing operation 500C is different than the feed material dispensed in operations 500A, 500E. However, the feed material delivered in operations 400A, 400C is the same.

As shown in FIG. 5A, the operation times for each of these operations 500A-500F may be similar. The operating time of action 500G may be relatively longer than the operating time of each of actions 500A-500F. Operations 500A-500F are each limited to dispensing and curing the feed material in a single layer, whereas operation 500G requires the application of microwaves to multiple layers, so operation 500G A longer operating time may be required so that the microwaves can induce sufficient crystallization within each of the first, second and third layers. The operation time of operation 500G may be 2-40 times longer than the operation time of each of operations 500A-500F. In some examples, the duration for which UV radiation is applied can be from 0.1 seconds per 0.01 square meters per layer to 1 second per 0.01 square meters per layer. In some cases, the duration for which microwaves are applied is independent of the number of layers. The duration can be, for example, 1 second to 20 seconds.

Continuous operations 500A-500F allow a second layer formed from a second feed material to be sandwiched between two layers formed from a first feed material. In particular, the first layer of the first feed material (dispensed and cured in operations 500A and 500B) is below the second layer of the second feed material (dispensed and cured in operations 500C and 500D). It is in. A third layer of the first feed material (dispensed and cured in operations 500E and 500F) is above the second layer of the second feed material. This arrangement of two feedstocks results in a layer of feedstock having a lower density of ceramic component disposed between two layers of higher density of ceramic component.

When the microwave source 122 applies microwaves to the first layer, the second layer, and the third layer (500 G), the microwave source 122 applies microwaves to the first and second feed materials. can cause crystallization of the ceramic component of , thereby causing crystallization in each of the first layer, the second layer, and the third layer. The layer having a lower density of ceramic components, i.e. the second layer, has smaller ceramic crystallites than the ceramic crystals formed in the two layers having a higher density of ceramic components, i.e. the first and third layers. to form The ceramic crystals formed in the first and third layers are, for example, 300% to 2000% larger than the ceramic crystals formed in the second layer. eg 300%-1200%, 400%-2000%, 1200%-2000% larger). The ceramic crystallite size ratio may depend on the difference in density of the ceramic components in the first and second feedstocks.

In addition to causing crystallization, microwaves can also cause sintering between ceramic crystals. The ceramic crystals formed in the second layer can be sintered into the ceramic crystals formed in the first and third layers by application of microwaves. The smaller grain size of the ceramic crystals formed in the second layer compared to the grain size of the ceramic crystals formed in the first and third layers can result in a stronger bond between the ceramic crystals. There is In particular, the smaller the grain size, the more dense the ceramic crystals and thus can promote stronger bonds between the crystals when sintered.

After the first, second, and third layers have been delivered, cured, and crystallized in operations 500A-500G, these operations are repeated to deliver, cure, and crystallize additional layers. can be As depicted in FIGS. 5A and 5B, if process 500 includes these additional layers, process 500 may include operation 500H to initiate dispensing of another layer of the first feedstock. . Process 500 can then continue with operations similar to operations 500B-500G where a new layer is cured, the next layer is delivered, cured, and each new layer is exposed to microwaves.

Controllers and computing devices can implement processes 400 and 500, operations 400A-400E, 500A-500H, and other processes and operations described herein. In some embodiments, control system 114 and controller 116 of device 100 control various components of device 100, such as dispenser 118, radiation source 120, microwave source 122, and/or actuators connected to these systems. , and can generate control signals for those components. Control system 114, controller 116, and other processors and controllers of device 100 may coordinate their respective operations to cause device 100 to perform the various functional operations or sequences of steps described above. These processors and controllers can control the movements and operations of the additive manufacturing module 104 , the microwave module 106 , and other systems of the apparatus 100 .

Some of the control system 114, controller 116, and other computing devices of the systems described herein may be implemented in digital electronic circuitry, or computer software, firmware, or hardware. For example, the controller may include a processor for executing a computer program product, eg, a computer program stored on a non-transitory machine-readable storage medium. Such computer programs (also known as programs, software, software applications, or code) may be written in any form of programming language, including compiled or interpreted languages, and may be written as stand-alone programs or modules, constructs. It can be deployed in any form including elements, subroutines, or other units suitable for use in a computing environment.

Control system 114, controller 116, and some of the other computing devices of the described system store data objects, e.g. A computer readable medium can be included. For example, the data object may be a file in STL format, a 3D Manufacturing Format (3MF) file, or an Additive Manufacturing File Format (AMF) file. For example, the controller can receive data objects from a remote computer. For example, a processor in control system 114, such as controlled by firmware or software, interprets data objects received from a computer and controls the components of apparatus 100 to fuse the specified pattern for each layer. can generate the set of signals required for

While this document contains details of many specific embodiments, these are not intended to limit the scope of any invention or what is patentable, but rather specific to specific embodiments of particular inventions. should be construed as a description of the features. Certain features that are described in this document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Further, although features have been described above and initially claimed as operating in certain combinations, one or more of the features from the claimed combination may sometimes be Combinations may be omitted and claimed combinations may cover sub-combinations or variations of sub-combinations.

A ceramic component formed from the processes and operations described herein may be a ceramic wafer. In some examples, the ceramic component is a silicon carbide monolith, tungsten carbide monolith, or other ceramic monolith.

A ceramic component can provide a conditioning disk for the system to condition the polishing pad. Conditioning discs may be embedded with or coated with diamond particles that act as abrasives to improve the ability of the pad to polish or condition. The shape of the conditioning disc, eg the position and curvature of any cutting edge, can be set by the 3D printing process. Additionally, the surface texture of the bottom surface of the conditioning disc, eg, surface roughness or the presence of cutting features on the bottom surface of the disc, can be produced by a 3D printing process.

In some implementations, additive manufacturing equipment 100 includes a heat source that can apply heat to the feedstock on platform 112 . The heat source may be a heat lamp for radiating heat toward the feed material to uniformly heat the feed material. A heat source may alternatively or additionally be coupled to platform 112 to provide heat to any feed material dispensed onto platform 112 . Additional heat from the heat source can increase the curing speed when curing radiation is applied to the feed material 110 . Also, additional heat can be used to increase the sintering and/or crystallization rate when microwaves are applied to feed material 110 .

In some examples, enclosure 102 is configured to hold an inert gas such as nitrogen gas. Apparatus 100 may include a gas system that circulates gas in and out of enclosure 102 . As the feedstock 110 is delivered onto the platform 112, the gas improves the crystallization process and reduces crystal formation defects, thereby improving the crystal growth uniformity of the ceramic component of the feedstock 110. can be done.

Silicon carbide is an example of a ceramic material that can form ceramic components produced using the processes and operations described herein. Other examples of ceramic materials include metal oxides such as ceria, alumina, silica, aluminum nitride, silicon nitride, or combinations of these materials. Feed material 110 may be dry ceramic particles combined with a curable component. Feed material 110 may be a ceramic powder in liquid suspension or a slurry suspension of material. Dispenser 118 dispenses a combination of a ceramic compound or ceramic precursor and a curable component into a carrier fluid, such as a high vapor pressure carrier such as isopropyl alcohol (IPA), ethanol, or N-methyl-2-pyrrolidone (NMP). can be sent in. The carrier fluid can be evaporated prior to application of microwaves or prior to application of curing radiation.

A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. for example,
* Although two separate modules have been described, the additive manufacturing module 104 and the microwave module 106, in some examples the platform does not need to move between modules for the application of curing radiation and microwaves. You can configure the device. Platform 112 can have a fixed horizontal position with respect to dispenser 118 , radiation source 120 and microwave source 122 .
* Dispenser 118 , radiation source 120 and microwave source 122 may be located within a single module or printhead that is movable to different positions above platform 112 .
* Sensing system 126 may include other suitable sensors for monitoring feed material 110 . Sensing system 126 can include, for example, an optical sensor that tracks the grain size of ceramic crystals as they crystallize in response to exposure to microwaves. Sensing system 126 may alternatively or additionally include a thermocouple to detect the temperature of platform 112 .
Accordingly, other implementations are within the scope of the claims.

Claims (15)

An additive manufacturing apparatus for forming a ceramic part, comprising:
a platform supporting the ceramic component to be formed;
a dispenser for dispensing multiple successive layers of feed material onto said platform, said feed material comprising a curable component and a ceramic component;
a radiation source that emits radiation toward the upper surface of the platform, such that the radiation cures the curable components of the feed material as or after each layer is delivered to form a cured polymer; a radiation source, comprising:
a microwave source for applying microwaves directed at said successive layers on said platform, said microwaves vaporizing said curable components of said feed material and causing crystallization of said feed material to cause said ceramic component. a microwave source configured to form a
a controller connected to the microwave source and having circuitry and/or a non-transitory computer readable medium , wherein during operation the microwave source generates microwaves to vaporize cured polymer of the feed; a controller that causes crystallization of a ceramic component of a material to form the ceramic component;
with
The feed material is a first feed material, the curable component is a first curable component, the ceramic component is a first ceramic component, and the dispenser comprises the first feed material and the second curable component. a feed of material onto said top surface of said platform, said second feed of material comprising a second ceramic component and a second curable component;
The apparatus of claim 1, wherein said first feedstock and said second feedstock comprise ceramic crystal seeds of different densities . The controller, having circuitry and/or a non-transitory computer-readable medium, during operation causes the dispenser to dispense at least two layers of feed material between each application of the microwaves, thereby causing the microwaves to dispense at least two layers of feed material. 2. The apparatus of claim 1 , wherein the wave is configured to simultaneously vaporize the cured polymer of the at least two layers of feed material. The controller, having circuitry and/or a non-transitory computer readable medium, during operation causes the microwave source to apply microwaves to cause the dispenser to dispense all of the successive layers of the feed material, and then: 2. The apparatus of claim 1 , configured to simultaneously vaporize the cured polymer of the successive layers of the feed material. The controller, having circuitry and/or a non-transitory computer readable medium, during operation causes the microwave source to apply microwaves to cause growth of the microwave transparent ceramic crystals to form the ceramic component. 2. The apparatus of claim 1 , configured to form a . 2. The microwave source of claim 1, wherein the microwave source is configured to emit the microwaves at a plurality of frequencies, the microwave source configured to sequentially emit the microwaves at each of the plurality of frequencies. Device. 2. The apparatus of claim 1, wherein the radiation source is an ultraviolet (UV) light source and the radiation is ultraviolet. 2. The device of claim 1, wherein the ceramic component comprises a liquid phase ceramic compound. said microwave source crystallizing said first ceramic component of said first feedstock to form first ceramic crystals and crystallizing said second ceramic component of said second feedstock; 2. The device of claim 1 , configured to form a second ceramic crystal, said first ceramic crystal being larger than said second ceramic crystal. The ratio of the first ceramic component to the first curable component of the first feedstock is greater than the ratio of the second ceramic component to the second curable component of the second feedstock. A device according to claim 1 . The controller, having circuitry and/or a non-transitory computer-readable medium, during operation causes the device to dispense a first layer of the first feed material on a top surface of the platform using the dispenser. let
curing the first layer of the first feed material using the radiation source;
dispensing a second layer of the second feed material onto the first layer using the dispenser;
curing the second layer of the second feed material using the radiation source;
using the dispenser to dispense a third layer of the first feed material onto the second layer;
curing the third layer of the first feed material using the radiation source;
2. The apparatus of claim 1 , wherein the microwave source is used to sinter multiple layers including at least the first layer, the second layer, and the third layer. 2. The apparatus of claim 1, further comprising an enclosure that is opaque to the microwaves, the enclosure supporting the platform and isolating the microwaves emitted by the microwave source from the environment. 12. The device of claim 11 , comprising a window that is opaque to said microwaves and transparent to at least infrared light. 10. An infrared heat sensor that emits infrared light through the window toward the top surface of the platform, the infrared heat sensor configured to detect the temperature of the feed material on the platform. 13. The device according to 12 . 2. The apparatus of claim 1, further comprising a horn coupled to said microwave source, said horn shaped to direct said microwaves emitted by said microwave source to a portion of the upper surface of said platform. . 2. The device of claim 1, wherein the ceramic component comprises one or more precursors of a ceramic compound.

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